1. Technical Field
The present invention relates to a printing technology which performs printing of image data for representing a predetermined image, and more particularly, to a halftone processing technique.
2. Related Art
In a printing apparatus, there is well known a dithering method or an error diffusion method as a halftone technique for performing a grayscale expression. Since the dithering method and the error diffusion method each have advantages and disadvantages, there has been in the related art a demand to combine the dithering method elements with the error diffusion method elements to perform the halftone process. For example, in JP-A-2001-352448 and JP-A-2001-177722 is disclosed a technique in which a threshold is periodically varied by applying a systematic dither mask of the dithering method to the threshold of the error diffusion method, so as to combine the dithering method element with the error diffusion method element to perform the halftone process.